1. If your game has a hub world like Angry Birds, when replaying an older level do the events start over again or you need to make it to when a level is completed you have to make it to where enemies respawn and objects unchanged?

2. As for keeping score, can score be kept for every level as you can accumulate points throughout the entire game, because I have an idea if the player keeps earning points they can unlock additional levels or something.

Like finishing a level rewards you with a thousand points, and repeated clearings earned you 50k points and unlocks a hidden world. This is to add replay value for a little while, think its doable?